1. Technical Field
The present invention relates to a method of forming a complete tire carcass.
More specifically, the present invention relates to a method of forming a complete carcass by connecting an inner carcass to an outer carcass comprising a tread and, preferably, a reinforced tread belt.
2. Background Information
Radial tires are known to be produced by forming the outer carcass on the inner surface of a toroidal body; forming the inner carcass separately on a special forming device; inserting the inner carcass inside the toroidal body and onto the inner surface of the outer carcass to form the complete carcass; detaching the inner carcass from the forming device; and separating the forming device from the toroidal body.
The toroidal body defines the central portion of a forming mold, which, prior to the curing process, is closed by a pair of lateral plates normally supporting the sidewalls of the tire.
The inner carcass is also known to be formed using a device comprising a central shaft; a collapsible annular element fitted to the central shaft and supporting an intermediate portion of the inner carcass; and two rings of radially movable arms for clamping, with respect to the central shaft, two beads incorporated in two flexible lateral walls of the inner carcass.
The above device provides for inserting the inner carcass inside the toroidal body, radially expanding the annular element so that the inner carcass adheres to the outer carcass to define a complete carcass, and releasing the complete carcass by collapsing the annular element and withdrawing the arms supporting the beads.
The above tire forming method involves several drawbacks owing to the fact that, in the interim between detaching the complete carcass from the forming device and applying the lateral plates to the toroidal body prior to curing the tire, the beads are free to oscillate axially on account of the poor rigidity of the lateral walls of the inner carcass.